[bumstein]

Hi folks!!

Sierra;

Just wondering if Hubs, steering knuckles, brakes etc are compatible between NT and WT?

I have a set of NT everything front and back but looking at upgrading to WT. I can get hold of a WT diff and axle housings bare, but want to make sure all the outer parts will still fit.

Clearly I'd need to replace axles themselves for WT ones or Chromos, what else wouldn't transfer?

Worth noting I'm also putting a BenT rear disc brake kit on.

Cheers all!
B)

[Gwagensteve]

Yes, front is all compatible. Rear brake backing plates are different (bearing retainer is 45˚ out, linings etc are different), but you're sorting that out with the disk conversion.

I think I have 1.0 hubs etc in my front end!

[bumstein]

Sweet!!

Thanks Steve!!

Also looking at Chromo axles. Now they are 26 splines if I'm not mistaken?

What are my options for diffs? I was going to put in air lockers later but perhaps I need to do this sooner?

If I'm understanding this correctly two rear diffs would work, or if I put in ARB air lockers would I need to put in two rears? Or change spider gears?

I really have no first hand experience with these setups

[Angus Martin]

To fit cromo axles in the front, you have to have 26 spline side gears. Most people just put a rear centre in which is obviously 26 spline.

Does anyone know if coily knuckles are also compatible with WT diffs?

[bumstein]

So would two NT rear diffs work? Are they 26 spline as well?

What about air lockers, which parts to they replace?

[sideways]

All Sierra rears are 26 spline and the fronts are 22. 2 NT rear diffs would work well, unless you want the taller WT diff ratio. You can put an airlocker in a 22 spline front diff to turn it into a 26 spline, it replaces the actual centre (not the whole 3rd member assembly, which many people call the centre).

If you want a locker then I'd get an airlocker and put it in the front 3rd member, put that in the back (giving you a rear locker with very little gear wear) and put your old rear 3rd member in the front. That way you wont have to swap the NT tailshaft yokes for WT ones too.

You can even bolt early 1l front drums onto a WT housing, I don't think anyone wants to do that though!

[bumstein]

Thanks for that!! I was considering going twin locked but perhaps that's a more sensible option for the short term

[bumstein]

Ok, so gearing.. I'm still trying. To get my head around a few things.

I haven't committed to a tyre size yet, but was thinking around 235/75R15.

I have 4.16 TF case gears.

I have NT diffs which are 3.9 ratio (if I'm correct), as opposed to 3.7 WT ratios.

Any suggestions on which would suit to bring gearing back to factory? Adjust tyre size or track down WT diffs?

Edit: I'd prefer to keep to a common tyre size rather than some obscure size

[Santos]

i'm also curious about the speedo cable output of the transfer cases. Can they be swapped around and would this correct speedometer reading if diffs are swapped?
I know its a small difference but when you got the parts out why not?

[bumstein]

Good going Santos!! I too am curious

[sideways]

So taking a stock SJ51 with FR78 tyres (27.3"), 3679rpm at 110.

With 4.16s and 235/75r15s (28.9") 3897

With 4.16s, 235/75s and WT diffs (3.727) 3716

4.16, 30s 3.909 3754

4.16, 31s 3.909 3633

FWIW a stock SJ70 is 3962@110

[bumstein]

Sounds like the NT diffs, 4.16's and 235/75R15's would work ok.. It's a bit of an increase in revs but not drastic.

Even with the air lockers I should be able to swap to WT ring and alter the gearing slightly later on right?

[sideways]

bumstein wrote:

Even with the air lockers I should be able to swap to WT ring and alter the gearing slightly later on right?

Yep.

[bumstein]

Your a legend mate!! Cheers!!

[Gwagensteve]

In my opinion it's too costly to bother swapping r&p between 3.7 and 3.9 (new crush sleeves and professional setup will cost circa $300 per diff) and I'd almost guarantee you couldn't pick the difference, especially offroad.

Run whatever is in better condition.

Speedo ratios are the same for all models as far as I know. That's the reason there is a small difference in diff ratio between NT with 27.3" tyres and wt with 26" tyres. I can't recall revs/km at the moment but it's marked on the speedo and is the same for nt and wt. (it's 637 revs/km or something)

Steve.

[rexhunta]

Bumstein I've got a set of 3.7s ring n pinions if you get stuck too, also a set of 3.9s. Took them out of both cars to go 5.12s.

[Santos]

I ask more for when buying second hand parts when available & cheap. Good point on the speedo I will check and confirm my 85 and 92.

Would you say there was no point putting 4.1 diffs on an NT? its only 0.2 difference as well

[Gwagensteve]

Not much point. (It is 5% though, not 0.2%)

[Santos]

i didn't put a percent sign 4.1-3.9 = 0.2

[bumstein]

rexhunta wrote:

Bumstein I've got a set of 3.7s ring n pinions if you get stuck too, also a set of 3.9s. Took them out of both cars to go 5.12s.

Thanks mate! Will have a look tomorrow

[bumstein]

rexhunta wrote:

Bumstein I've got a set of 3.7s ring n pinions if you get stuck too, also a set of 3.9s. Took them out of both cars to go 5.12s.

Thanks mate! Will have a look tomorrow